Tournasian-early Visean mud mounds (i.e.,
Waulsortian and Waulsortian-like mounds) are unlike other carbonate buildups
in the stratigraphic record because they lack an identifiable frame-building
organism. Waulsortian mounds are comprised mainly of carbonate mud; Waulsortian-like
mounds are mud-rich and contain a significant percent of skeletal grains,
especially crinoids and bryozoa. This study has revealed that all of the
reported Waulsortian and Waulsortian-like mounds developed in low paleolatitudes
either on the southern shelf margin of the Laurussian paleocontinent or
in the Laurussian interior seaway. Waulsortian and Waulsortian-like mounds
are specifically not present in low-latitude regions of other paleocontinents.
As Tournasian-early Visean carbonate deposition was widespread in the range
of 30 degrees north to 10 degrees south, the very restricted paleogeographic
distribution of Waulsortian and Waulsortian-like mound locations suggests
a mechanism or set of conditions which effectively limited the distribution
of mud mounds. While considering the Tournasian-early Visean distribution
of paleocontinents and the applying principles which govern the movement
of modern hurricanes, tropical storms, and winter storms, this paper shows
that the tracks of hurricanes, tropical storms, and winter storms probably
corssed all main submerged paleocontinental areas except the southern Laurussian
shelf margin and the Laurussian interior seaway, the two areas where mud
mounds developed. This paper suggests that lack of storm energy in these
two large areas of Laurussia provided long- term stability and thus enhanced
the growth prospects of the frame-deficient Waulsortian and Waulsortian-like
mud mounds. Lack of extensive, periodic wave reworking and other storm-
induced devastation helps to account for enigmatic features such as general
mound symmetry, great size, high depositional relief (as much as 220 m),
and side steepness (as steep as 50 degrees).

INTRODUCTION

Waulsortian and Waulsortian-like carbonate
mud-rich mounds (called "reef mounds" by some; e.g., James, 1984)
contain pelmatazoan crinoids, fenestellid bryozoans, Stromatactis,
and various minor allochemical constituents, but lack a frame-building
organism (James, 1984). These mounds were the only type of organic buildup
known to have formed during the period of strongly suppressed reef building
that followed the Late Devonian collapse of the reef-building biotic community.
Waulsortian and Waulsortian-like mounds are limited to early Carboniferous
strata ranging in age from earliest Tournaisian (Tn1) (Smith, 1982) to
early Visean (V1a) (Lane, 1978; Lees, Hallet, & Hibo, 1985; see also
papers in Bolton, Lane, & LeMone, 1982). Mid- to late Visean,
Namurian, and younger Carboniferous mounds contain frame-building organisms
such as corals, bryozoans, and algae (Heckel, 1974; West, 1988) and thus
these non-Waulsortian mounds are excluded from consideration in this paper.
Although some authors regard all Tournaisian-early Visean mounds as "Waulsortian,"
herein I distinguish Waulsortian mounds and Waulsortian-like mounds on
the basis of some compositional and structural differences between the
two mound groups (see also discussion in Lees & Miller, 1985; Miller,
1986).

Waulsortian mounds occur in several
sites in western Europe (Belgium, Ireland, southern Wales, and northern,
central, and southern England) and in at least two sites in North America
(Sacramento Mountains of New Mexico and Big Snowy Mountains of Montana;
Lees & Miller, 1985; Miller, 1986). Waulsortian-like mounds occur at
many locations along the coeval Burlington-Lake Valley shelf margin that
extended from the midwestern U.S. (Illinois, Missouri, Arkansas, Oklahoma,
and Kansas) and through the southwestern U.S. (Texas, New Mexico, and Arizona)
(Gutschick & Sandberg, 1983; Lane, 1984). Waulsortian-like mounds are
also known from sites in the central Montana trough (Smith, 1982; Precht
& Shepard, 1989), the Williston basin of North Dakota and adjacent
Manitoba (Davies, Edwards, & Flach, 1989), and the Peace River embayment
of Alberta and adjacent British Columbia (Davies et al., 1989).

The nature and origin of Waulsortian
and Waulsortian-like mounds have been topics of interest and discussion
for more than 125 years (Miller, 1986). A compelling reason for the interest
in Waulsortian and Waulsortian-like mounds is their uniqueness in the geological
reef record owing to their total lack of a frame-building organism (James,
1984). Currently, there are three main theories to explain the probable
origin of these mounds. The lithoherm theory enlists penecontemporaneous
cementation as a key agent in mound formation (Neumann et al., 1977)
and suggests that modern lithoherms in the Straits of Florida are at least
partial analogues for Waulsortian and Waulsortian-like mounds. A proposed
microbial origin for mounds calls on organic films and filaments to stabilize
and support the carbonate mud during mound development (Miller, 1986).
An origin of the mounds by "baffling" or trapping of carbonate fines within
stands of crinoids and bryozoa has been proposed to account for some of
the Waulsortian-like mounds which contain a relatively high skeletal fossil
content (e.g., King, 1986). It is also likely that two or all three
of the proposed mechanisms listed above acted in concert to produce some
mounds (Pratt, 1982; James, 1984; Brown & Dodd, 1990).

The petrology and paleontology of most
important mounds have been well documented (see citations in West,
1988), but a comprehensive understanding of Waulsortian and Waulsortian-like
mound origin awaits further research. As a contribution toward further
understanding of mound development from a global perspective, I discuss
herein Tournaisian-early Visean (ca. 360- 348 Ma; Ross & Ross,
1987) geography and the probable influence of that paleogeography on paleo-storm
tracks relative to the formation of Waulsortian and Waulsortian-like mud
mounds.

MOUND CHARACTERISTICS

Waulsortian mounds are composed predominantly
of carbonate mud and include a subordinate amount of allochemical debris
(Lees et al., 1985). In contrast, Waulsortian-like mounds are composed
of a wider diversity of allochemical constituents than the European Waulsortian
mounds (Miller, 1986) and comprise a carbonate mud- rich core and surrounding
flank beds that are generally rich in pelmatazoan crinoid debris (Wilson,
1975). Both Waulsortian and Waulsortian-like mounds lack fossil evidence
of a frame-building organism (James, 1984).

Waulsortian and Waulsortian-like mounds
occur in association with downslope sedimentary facies that include cherty
limestones, basinal carbonates and shales, and resedimented carbonate-debris
facies (Wilson, 1975; King, 1986), and the mounds are universally interpreted
as regional shelf-margin and foreslope features (e.g., see papers
in
Bolton et al., 1982). Whereas most Waulsortian and Waulsortian-like
mounds were several metres high, individual mounds in New Mexico attained
depositional relief as great as 105 m (Lane, 1984) and, in Belgium, 220
m (Lees et al., 1985). Waulsortian and Waulsortian-like mounds are
generally symmetrical; the mounds are crudely layered and may have steep
sides (as much as 50 degree slopes) (Wilson, 1975).

Lees et al. (1985) and others
have noted that Belgian Waulsortian mounds evolved through four depth-related
stages. The initial stage is rich in pelmatazoan crinoids and fenestellid
bryozoans and developed at depths that were probably aphotic. The upper
stages are all mud rich and are distinguished by differences in the relative
abundances of several minor allochemical constituents. The partitioning
of allochems among the depth-related stages is related most strongly to
differences in photic level rather than to differences in physical energy
(data in Lees et al., 1985). The uppermost stage of many Belgian
mounds contains a minor component of coated grains and calcareous algae
suggesting the influence of shallow-water depositional conditions. In Waulsortian-like
mounds, thin, shallow-water (or "capping") facies are characterized by
hardgrounds and colonial corals (e.g., Syringopora) (Smith, 1982;
King, 1986). Biostratigraphic study of mounds (Lees et al., 1985)
has shown that shallow-water facies are coeval and are probably related
to episodic drops in relative sea level (e.g., the end-Tournaisian
eustatic sea-level drop; Ross & Ross, 1987).

PALEOGEOGRAPHY

Global geography at the time of Waulsortian
and Waulsortian-like mound development included a large open ocean (Panthalassa)
surrounding a relatively closely spaced group of continents. In Figure
1, a current Visean global reconstruction (from Rowley, Raymond, Parrish,
Lottes, Scotese, & Ziegler, 1985) represents the prevailing geography
during mound development. Use of the Visean global reconstruction is appropriate
because the relative positions of Laurussia and Gondwana changed only slightly
over the Tournaisian-Visean interval, and the relatively slow rate of Laurussian
drift only moved that paleocontinent approximately 1 degree south during
the Tournaisian-early Visean (drift rate from Ross & Ross, 1985). The
Visean positions of Laurussia and Gondwana are well established and have
not been modified since the initial paleocontinental base maps were published
(Scotese, Bambach, Barton, Van Der Voo, & Ziegler, 1979; Rowley etal.,
1985). For the smaller paleocontinental blocks (Indochina, North China-Tsaidam,
South China, Shan Thai-Malaysia, and Tarim; Fig.
1), much less evidence exists to support their respective paleogeographic
positions (especially Indochina and Shan Thai-Malaysia), and their positions
are partially speculative (Rowley et al., 1985).

Figure 1 shows that the known Waulsortian
and Waulsortian-like mounds developed on the Laurussian paleocontinent
in two broad paleogeographic settings. Numerous mounds developed on the
southern Laurussian shelf margin (i.e., on the northern margin of
the Appalachian-Ouachita ocean) within 5 degrees of the paleoequator (Fig.
1). Several mounds also developed within the Laurussian interior seaway
up to 25 degrees N (Fig. 1). The Laurussian
interior seaway encompasses the Antler foreland basin, the central Montana
trough, the Williston basin, and the Peace River embayment (see maps in
Precht & Shepard, 1989; Davies et al., 1989).

PALEOCLIMATES AND PALEO-UPWELLING

Precise paleotemperature measures are
lacking for the Tournaisian-early Visean, however, some general statements
can be made about the climates during this time. According to the first-order
climatic curve of Fischer (1982), the early Carboniferous (Tournaisian-early
Visean) was a time of transition in long-term global regimen from a "greenhouse"
world to an "icehouse" world. The sum of available petrologic and paleontologic
evidence supports the concept of an ameliorating Tournaisian-early Visean
climate that was relatively warm (Dickens, 1985; Raymond, 1985; Rowley
et
al., 1985; Raymond, Kelley, & Lutken, 1989) as compared to the
Carboniferous in general as well as in comparison to the present (Fischer,
1982). Further, the Tournaisian-early Visean was relatively humid, especially
at low latitudes, as compared to the Carboniferous in general (Van der
Zwan, Boulter, & Hubbard, 1985; Rowley et al., 1985).

Latitudinal generic diversity studies
of brachiopods and selected fossil plant species show that the Tournaisian-early
Visean world, as compared with that of the mid- to late Visean and Namurian,
supported more generic diversity in a narrower, more nearly equatorial
realm (Raymond, 1985; Raymond et al., 1989). These studies provide
evidence of a distinctive, relatively warm, tropical zone extending from
about 30 degrres north to 10 degrees south paleolatitude (Raymond et
al., 1989) during the time when Waulsortian and Waulsortian-like mounds
developed.

Atmospheric circulation patterns in
the Visean (based on the Scotese et al., 1979 reconstruction) likely
contributed to significant seasonal upwelling of nutrient-rich ocean waters
at selected sites astride the Tethys and Appalachian-Ouachita ocean (Parrish,
1982). According to the predicted-upwelling maps in Parrish (1982), year-round
upwelling brought such waters to areas of Laurussia encompassed by Waulsortian-like
mound sites 5 through 10 (Fig. 1) while the
region of Waulsortian mound sites 1 through 4 (Fig.
1), did not receive upwelling ocean waters. Visean seasonal upwelling
also affected minor regions without Waulsortian and Waulsortian-like mud
mounds, including the coast of the Appalachian highlands (ApHL on Fig.
1) and three sites on Gondwana (the northeastern coast of South America,
northern Arabia, and the northwestern shelf of Australia; Parrish, 1982).

PALEO-STORM TRACTS

Hurricanes and tropical storms are important
climatic forces acting upon the marine sedimentary realm in general and
upon reefs in particular (Woodley et al., 1981; James, 1984). Thus,
the energy of such storms and their effect on mound growth is of interest
in more completely understanding Waulsortian and Waulsortian-like mound
genesis. In the modern ocean, sea-surface temperature is the primary limiting
factor in the generation of hurricanes and tropical storms (Palmen &
Newton, 1969; Anthes, 1982). An actualistic extension of this principle
is supported by recent preliminary syntheses of hurricane and tropical-storm
influences in the Paleozoic and Mesozoic record (Marsaglia & Klein,
1983; Barron, 1988). From these investigations, I infer that the relatively
warm and humid low-latitude climate of the Tournaisian-early Visean world
probably spawned frequent and intensive hurricanes and tropical storms.

Barron (1988) has reasoned that paleogeography
(specifically paleocontinental positions, paleotopography, and extent of
paleocontinental flooding) and paleoclimate (especially the continuity
of subtropical high-pressure zones) played major roles in controlling the
specific heading of hurricane and tropical storm tracks in the past. Under
conditions somewhat analogous to those prevailing during modern Pacific
typhoon genesis (Gray, 1968; Marsaglia & Klein, 1983), the large Panthalassa
ocean (Fig. 1) likely would have been an
effective breeding ground for hurricanes and tropical storms. Hurricanes
and tropical storms also likely developed in the Tethys (Fig.
1) as they frequently do in the modern Caribbean-Gulf of Mexico (Gray,
1968). Like modern equivalents, Carboniferous hurricanes and tropical storms
would have formed over open water just outside the narrow intertropical
convergence zone (ITCZ) and moved initially westward. Subsquently, the
hurricanes and tropical storms would have veered away from the ITCZ (see
plots of modern storm tracks in Palmen & Newton, 1969).

The probable tracks of some Tournaisian-early
Visean hurricanes and tropical storms nucleating in the eastern Panthalassa
ocean would have lead ultimately onto the continental shelves of North
China-Tsaidam, Tarim, and Kazakhstania and the northern shelf system of
Gondwana, including the South China platform, the Shan Thai-Malaysia block,
and the northern basins of Australia (Fig. 1).
It is notable that Waulsortian and Waulsortian-like mounds are specifically
not present in the aforementioned, storm-influenced, paleocontinental shelves
(Brown, Campbell, & Crook, 1968; Nalivkin, 1973; Metcalfe, 1983; Shipu,
Yintnag, Guanxiu, Zhiping, & Shizhong, 1983). The known mounds are
instead confined to the southern shelf margin of the Laurussian paleocontinent
and the connecting Laurussian interior seaway (Fig.
1).

Owing to probable steering by subtropical
high-pressure systems (Barron, 1988), any hurricane or tropical storm entering
the Appalachian-Ouachita ocean from the eastern Tethys via the relatively
narrow Tethyan strait would likely have followed one of two general tracks
(Fig. 1). First, the storm might travel approximately
due west and encounter the Appalachian highlands, thus dissipating its
energy and/or deflecting its path in a southwesterly direction. Second,
the storm could have followed an arcuate, southwest-directed (Southern
Hemisphere) track that would take it roughly parallel to the northern coast
of Gondwana (Marsaglia & Klein, 1983). Hurricane and tropical-storm
deposits in the Visean of northwest Africa (Fig.
1) provide evidence in support of this second scenario (Kelling &
Mullin, 1975). In either scenario, any Tournaisian-early Visean hurricane
or tropical storm would have been a Southern Hemisphere storm, because
of the low south-latitude position of the Tethyan strait.

The paleogeographic arrangement of the
Appalachian-Ouachita ocean and the connecting Laurussian interior seaway
(Fig. 1) probably prevented these bodies
of water from being conducive to the nucleation of hurricanes and tropical
storms for two reasons. First, the northern margin of the Appalachian-Ouachita
ocean, i.e., the shelf system of southern Laurussia, was situated at very
low latitudes (within a few degrees above and below the paleoequator; Fig.
1) and, therefore, probably was within the equivalent of the modern
ITCZ (i.e., the equatorial doldrums), a zone of weak winds and very
little storm activity (Neiburger, Bonner, & Edinger, 1973; Marsaglia
& Klein, 1983). To examine the second reason, it is important to note
that the modern hurricane and tropical-storm season is at its hemispheric
peak during the summer and early fall, when the ITCZ departs most strongly
from the equator (Hayes, 1967; Marsaglia & Klein, 1983). From this
fact we can infer that, during the Northern Hemisphere summer and early
fall, the Tournaisian-early Visean ITCZ would have been situated somewhere
over the southern part of the largely emergent Laurussian paleocontinent
and, therefore, would not have generated any hurricanes and tropical storms
which might have impinged upon southern Laurussian shelf systems. Perhaps
partly for this reason, Waulsortian and Waulsortian-like mound development
is prolific in this storm-protected southern Laurussian shelf setting (Fig.
1).

Any possible nucleation of a hurricane
or tropical storm within the Laurussian interior seaway was probably mitigated
by the local topography. Key topographic features around the interior seaway
included the extensive Antler highlands on the paleocontinental western
margin, the emergent Laurussian lowlands to the east, and the Transcontinental
arch to the south (Fig. 1) (Lane, 1984; Rowley
et
al., 1985). In addition to the paleotopographic features just noted,
the overall ocean-continent arrangement of the Tournaisian-early Visean
world was probably unfavorable for the positioning of Northern Hemisphere
subtropical high-pressure cells critical for steering storms into a narrow
interior seaway (see discussion of steering in Barron, 1988; see also Barron
& Parrish, 1986).

Other severe storms, such as winter
storms, are attributable to the effect of gross jet-stream patterns. Today
these patterns are strongly linked to geography and are the cause of significant
temperature contrasts and elevated wind speeds on the eastern oceanic margins
of continents (Blackmon, Wallace, Lau, & Muller, 1977). Compilation
of data on storm beds in the mid-latitude stratigraphic record of eastern
paleocontinental margins (Marsaglia & Klein, 1983) indicates that gross
jet-stream patterns generated winter storms throughout much of the Paleozoic
and Mesozoic. Waulsortian and Waulsortian-like mounds are absent on the
east-facing (i.e., winter storm-affected) oceanic margins of the
paleocontinents (Fig. 1). For example, Waulsortian
and Waulsortian-like mounds are specifically not present in the well-developed
Tournaisian-early Visean section on the Laurussian eastern margin (i.e.,
the Donetz basin and other eastern basins, U.S.S.R.; Fig.
1) (Nalivkin, 1973; Aisenverg et al., 1979).

DISCUSSION

My paleogeographic analysis shows that
the known Waulsortian and Waulsortian-like mounds were confined to two
broad Laurussian regions which appear to have been protected from potential
severe-storm tracks. Thus, there was probably a connection between low
wave energy (because of the lack of hurricane, tropical-storm, and winter-storm
wave influences) and mound development.

If the control on Waulsortian and Waulsortian-like
mound development were strictly latitudinal, as in most carbonate deposition,
mounds would have developed in various low-latitude locations (probably
between 30 degrees north and 10 degrees south), including the northern
shelf margin of Gondwana and shelf margins of Kazakhstania, Tarim, and
North China-Tsaidam. However, no such mounds are known in the Tournaisian-early
Visean carbonate stratigraphy of the aforementioned storm-influenced paleocontinental
settings.

If the Visean paleocontinental positions
of Indochina, North China-Tsaidam, and Shan Thai-Malaysia are correct (Fig.
1), the equatorial Indochinese block and the near-equatorial regions
of the other two paleocontinental blocks just mentioned would have been
potential sites for development of Waulsortian and Waulsortian-like mound
development. However, in these areas the Tournaisian is absent at nearly
all locations and the minor Tournaisian-early Visean section consists almost
entirely of coarse clastics and shales (Metcalfe, Idris, & Tan, 1980;
Metcalfe, 1983; Shipu
et al., 1983).

If the control on distribution of Waulsortian
and Waulsortian-like mounds were related closely to atmospheric circulation
in general and the attendant seasonal upwelling of nutrient-rich waters
in particular, mud mounds would occur at all sites of predicted seasonal
upwelling. Yet several predicted coastal upwelling zones lack Waulsortian
and Waulsortian-like mound development (e.g. northeastern South
America and two other regions on the paleocontinent of Gondwana; Parrish,
1982). Further, the region of Laurussia where European Waulsortian mound
growth occurred lacked the benefits of upwelling waters according to predicted
patterns (Parrish, 1982).

Theories on the origin of specific Waulsortian
and Waulsortian-like mounds must account for mound growth in the absence
of any frame-building organism. I suggest that frame-building organisms,
the hallmark of organic buildups throughout the Phanerozoic, were not essential
to Waulsortian and Waulsortian-like mound growth in part because of the
general absence of wave energy from hurricanes, tropical storms, and winter-storms
during mound growth. The dearth of storm energy would help explain the
general symmetry of many Waulsortian and Waulsortian-like mounds as well
as the tendency for persistence of steep sides on the larger mounds (Wilson,
1975). Further, the lack of severe storms would mean a prevailingly shallow
wave base. A shallow wave base over an extended period of time could help
explain why Waulsortian and Waulsortian-like mounds attained significant
depositional relief without showing many effects of periodic wave reworking.
The apparent connection between low wave energy and mound development does
not shed much light on the question of which specific mechanism (i.e.,
cementation, microbial binding, or baffling) best explains Waulsortian
and Waulsortian-like mound origin. As Pratt (1982), James (1984), and Brown
& Dodd (1990) have noted, it is likely that two or three mechanisms
may have been at work at the same time in many mounds, and further study
on mound-building mechanisms is needed.

ACKNOWLEDGMENTS

I am grateful to Dr. A.M. Ziegler, who
provided the base map for my Figure 1 in
1989 while it was still unpublished information. My interest in the "Waulsortian
problem" is a spinoff from my dissertation research on Waulsortian-type
facies of Boone County, Missouri (King, 1980), which was directed by Dr.
Tom Freeman, University of Missouri-Columbia. This web paper is a modified
version of the one published by me in Geology (King, 1990).

EPILOGUE

In August 1990, while attending the
I.A.S. quadrennial meeting in Nottingham, U.K., I met J.D. Cooper, California
State University, Fullerton, who had been supervising a senior thesis project
on a Waulsortian-type mound in the Tin Mountain Formation of eastern California
(Milligan, 1992). Dr. Cooper also told me of similar and related work on
three Waulsortian-type mounds at an adjacent site in eastern California
done by D.L. Jones, who was then a graduate student at the University of
California-Riverside (Jones, 1988; 1989). All these studies in California,
unknown to me when I wrote my original paper (King, 1990), would fit nicely
as new data points on my Figure 1. In fact,
it might have been predicted that Waulsortian mounds would occur at the
western coast of North America based on inferences in my paper. Reference
to Figure 1 shows how that region of western
North America, during Early Carboniferous, was a protected zone with respect
to tropical storms and hurricanes.

In late 1990, a few months after publication
of the original version of this paper in Geology I was asked to
write a 'Reply' to a 'Comment' on my paper, which had been submitted to
the editors by V.P. Wright. Our mutual 'Comment-Reply' appears on pages
413-414 in the 1991 volume of
Geology (Wright, 1991; King, 1991).
Dr. Wright had several criticisms of my work, but the most significant
criticism was that Waulsortian mound development took place, he said, at
depths too great for storm waves to have played a role in mound disruption.
In my 'Reply,' I pointed out that Early Carboniferous sea-level changes
evidently brought Waulsortian mounds to shallower depths at times. In my
opinion, it is important to note that there is a large body of literature
on Waulsortian mounds, which describe many different realms of depth for
their development. Thus, I think the "too deep" argument is not valid.

In 1995, I.A.S. Special Publication
23, titled Carbonate Mud-Mounds, Their Origin and Evolution, was
published.Two articles in that Special Publication cover Waulsortian
mounds and both of them contain a critique my previous work, which iscited
above (i.e., King, 1986; 1990). These papers are by Bridges, Gutteridge,
& Pickard (1995) and Lees & Miller (1995).

Bridges, Gutteridge, & Pickard (1995),
while not seeming to have a problemwith my mound descriptions,
criticize my usage of the terms "Waulsortian and Waulsortian-type" because
in their view such terms are of "limited valuebecause they do not
immediately convey a particular form." What these researchers resist concluding
from the growing body of literature on global Waulsortian facies is that
there is considerable diversity within what we call "Waulsortian," i.e.,
there is NOT a "particular form" of Waulsortian all around the world. Perhaps,
instead of arguing over semantics, we should find another, more inclusive,
term for this facies.

"King (1990), taking a world view of mid-Dinantian paleogeography
and paleoclimates, proposed that Waulsortian and similar mounds only formed
in sea areas protected from hurricanes, tropical storms, and winter storms.
The degree of wave activity doubtless influences sedimentation in shallow
water, but it is not easy to understand how waves could control the formation
of Waulsortian banks which seem to have favoured relatively deep waters
below storm wave base (perhaps to 300 m or more, see, for example, Lees
1982, Fig. 8)."

Whereas I appreciate the attention of
Drs. Lees and Miller to my work, they (like V.P. Wright, discussed above)
have missed out on a key point: namely, that Early Carboniferous sea-level
changes evidently brought Waulsortian mounds to much shallower depths at
times(e.g., see Burchette, 1990, p. 106). Further,
there are two other possible explanations of how storms might affect deep-water
mounds not considered by Drs. Lees and Miller. First, such mounds may have
been indirectly influenced by storm energy if violent storms initiated
significant mass-movement of fine shelfal debris into deeper water, thus
smothering growing mounds. And secondly, particularly intensive storms,
perhaps more intensive than the largest modern hurricanes, may have generated
waves that acted at depths that penetrated significantly into the Waulsortian
realm.

In 1998, I received a communication
from Dr. H.E. Cook, USGS-Menlo Park, California, saying that he had been
working on carbonate systems in the former Soviet Union with a group of
Kazakhstanian geologists. He reported that they had discovered Waulsortian-like
mounds in Early Carboniferous strata of the Bolshoi Karatau Mountains of
southern Kazakhstan (Cook, Zhemchuzhnikov, Buvtyshkin, Golub, Gatovsky,
& Zorin, 1994), which were not known about when I wrote my paper. He
also related that his research group would be publishing about this Waulsortian
mound development in a forthcoming (1999?) SEPM Special Publication, tentatively
titled Carbonate Systems of the CIS. Dr. Cook pointed out that his
new Waulsortian mounds developed on what was then the eastern side of Kazakhstania
(Fig. 1), and he implied that such a discovery
challenged my arguments about storm control. I do not think his discovery
shows any problems with my interpretations, as the Tarim block (Fig.
1) would have provided some protection from incoming storms. Further,
the newer paleogeographic map by Scotese & McKerrow (1990), which was
cited by Cook and his colleagues, shows Kazakhstania in a more closely
spaced configuration with respect to Tarim. Such a location makes the prospect
of storm impact on eastern Kazakhstania even less likely.

KING, D.T., JR. (1990) Probable influence of early Carboniferous (Tournaisian-early
Visean) geography on the development of Waulsortian and Waulsortian-like
mounds. Geology, 18, 591-594.

KING, D.T., JR. (1991) Reply to Comment on "Probable influence of early
Carboniferous (Tournaisian-early Visean) geography on the development of
Waulsortian and Waulsortian-like mounds." Geology, 19, 413-414.